TY - JOUR
T1 - Proteasome inhibitors suppress formation of polyglutamine-induced nuclear inclusions in cultured postmitotic neurons
AU - Kim, Woo Yang
AU - Horbinski, Craig
AU - Sigurdson, Wade
AU - Higgins, Dennis
PY - 2004/12
Y1 - 2004/12
N2 - At least nine neurodegenerative disorders are caused by expansion of polyglutamine repeats in various genes. This expansion induces the formation of nuclear inclusions (NI) within various cell types. In this study, we developed a model for polyglutamine diseases using primary cultures of sympathetic neurons from the superior cervical ganglia of prenatal rat pups. Transfection with a plasmid encoding 127 glutamine repeats causes NI to develop in ∼70% of the sympathetic neurons within 6 days. In addition, it causes somatic atrophy and inhibits dendritic growth. The NIs contain ubiquitinated proteins and sequester the molecular chaperone heat shock protein 70 (Hsp70). We found that two specific proteasome inhibitors, lactacystin and CEP1612, suppress thezformation of polyglutamine-induced NI. In addition, lactacystin treatment induced the removal of preexisting NI. Western blotting and immunocytochemistry revealed that lactacystin and CEP1612 strongly induce the expression of Hsp70, whereas less specific proteasome inhibitor such as N-acetyl-Leu-Leu-Norleucinal does not. Coexpression of 127 glutamines with a plasmid encoding wild-type Hsp70 gene resulted in a marked reduction of the percentage of neurons containing NI. In addition, transfection with plasmids encoding mutant Hsp70 blocked the effects of lactacystin. These findings further implicate Hsp70 as a neuroprotective molecule and they suggest the potential utility of certain proteasome inhibitors in the treatment of polyglutamine diseases.
AB - At least nine neurodegenerative disorders are caused by expansion of polyglutamine repeats in various genes. This expansion induces the formation of nuclear inclusions (NI) within various cell types. In this study, we developed a model for polyglutamine diseases using primary cultures of sympathetic neurons from the superior cervical ganglia of prenatal rat pups. Transfection with a plasmid encoding 127 glutamine repeats causes NI to develop in ∼70% of the sympathetic neurons within 6 days. In addition, it causes somatic atrophy and inhibits dendritic growth. The NIs contain ubiquitinated proteins and sequester the molecular chaperone heat shock protein 70 (Hsp70). We found that two specific proteasome inhibitors, lactacystin and CEP1612, suppress thezformation of polyglutamine-induced NI. In addition, lactacystin treatment induced the removal of preexisting NI. Western blotting and immunocytochemistry revealed that lactacystin and CEP1612 strongly induce the expression of Hsp70, whereas less specific proteasome inhibitor such as N-acetyl-Leu-Leu-Norleucinal does not. Coexpression of 127 glutamines with a plasmid encoding wild-type Hsp70 gene resulted in a marked reduction of the percentage of neurons containing NI. In addition, transfection with plasmids encoding mutant Hsp70 blocked the effects of lactacystin. These findings further implicate Hsp70 as a neuroprotective molecule and they suggest the potential utility of certain proteasome inhibitors in the treatment of polyglutamine diseases.
KW - Heat shock protein 70
KW - Molecular chaperone
KW - Nuclear inclusion
KW - Polyglutamine diseases
KW - Proteasome inhibitor
UR - http://www.scopus.com/inward/record.url?scp=9744278199&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=9744278199&partnerID=8YFLogxK
U2 - 10.1111/j.1471-4159.2004.02788.x
DO - 10.1111/j.1471-4159.2004.02788.x
M3 - Article
C2 - 15569248
AN - SCOPUS:9744278199
VL - 91
SP - 1044
EP - 1056
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
SN - 0022-3042
IS - 5
ER -